Method of cold reducing



Aug. 11, 1970 w, -:5 JR" ET AL- 3,523,437

METHOD OF GOLD REDUCING Filed Dec. 7, 1967 Need/e Valve /2 Adjustment INVE/V TORS.

JOHN W BALES, JR. and I B W/LLYAM 5'. MILLER Attorney United States Patent METHOD OF COLD REDUCING John W. Bales, In, North Huntingdon Township, Westmoreland County, and William G. Miller, Penn Hills Township, Allegheny County, Pa., assignors to United States Steel Corporation, a corporation of Delaware Filed Dec. 7, 1967, Ser. No. 688,780

Int. Cl. BZlb 45/02 US. Cl. 72-43 4 Claims ABSTRACT OF THE DISCLOSURE An improved method of cold reducing metal work is described which involves first lubricating the work by atomizing a liquified oil lubricant with gas of a temperature which precludes solidification of the oil. The work is coated with the atomized oil and then cold reduced.

This invention relates to an improved process of cold reducing metal work such as strip, sheet or the like. More particularly, the invention concerns an improved process which includes lubricating the work in a particular manner to aid the cold reduction.

The lubrication of metal work prior to cold reduction is well known, and many lubricants and methods of applying same have been practiced by the metal industries. In particular, the cold reduction of steel strip, sheet, etc., often requires the application of a lubricant to facilitate working; and improve the quality of the product produced. The conventional method of applying lubricants, e.g., cold rolling lubricants, on cold reduction mills, is to flood the work at the roll bite with a lubricant delivered by a system of spray headers, pumps, tanks, etc. The commonly used lubricant consists of 5 to 20% concentration of oil mixed with water essentially as an emulsion. Although the concentration of oil is relatively low, great quantities are required. In addition to high oil consumption, a further disadvantage of the oil emulsion lubricating technique is the poor appearance of the final product which frequently results. The emulsion tends to streak the surface of the work and results in a surface undesirable for many purposes. However, the use of 'oil lubricants, i.e., substantially all oil, is very diflicult because many of the better lubricants are either viscous or solid at room temperature.

The present invention avoids the disadvantages of the prior cold reduction practices by providing a relatively less expensive and highly efiicient lubricating and cold rolling process. Accordingly, the invention involves an improved process of cold rolling which comprises applying a cold rolling lubricant by atomizing a liquified oil with gas of a temperature sufficient to preclude solidification of said oil, coating a surface of metal work with said atomized oil and thereafter cold reducing the lubricated work.

A part of the invention is the discovery that a substantially all oil lubricant not containing any water may be successfully used in cold reduction if it is applied by atomizing oil in a liquified condition onto a surface of metal work prior to cold reducing. The use of rolling oils such as neat oil alone has proven superior to the use of rolling oil emulsions. Much less rolling oil is required to obtain the final reduction. However, to obtain optimum economy of operation and to insure sufficient lubrication of the work during working, e.g., rolling, the oil must be applied in a liquified atomized form, i.e.,- a mist.

The invention will be more fully described in connection with the accompanying drawings in which:

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FIG. 1 is a schematic view of one embodiment of the invention, illustrating the application of atomized lubricant onto metal work prior to cold rolling; and

FIG. 2 is a schematic sectional view of an atomizing nozzle useful in the system described in FIG. 1.

As shown in FIG. 1, a lubricant in a liquified condition, which may be hot oil, is pumped from a storage tank 10 through a conduit 12 to a plurality of nozzles 14 adapted to be positioned above and below the work entering the cold reduction mill 20. In the embodiment illustrated, the cold reduction mill is a cold rolling mill. Gas, preferaby air, of a temperature sufficient to preclude solidification of the oil is supplied to the nozzles 14 by a conduit 24. The gas is heated by a heater, not shown, so that upon contact with the oil it will not solidify same or increase the oils viscosity by cooling it to an undesirably low temperature. The heated supply lines and warm gas are necessary for lubricants which are nearly solid at room temperature.

The lubricant supply lines 12 may be heated through the use of steam-traced pipe as shown in FIG. 2. In this embodiment, a steam line 11 is constructed to run parallel and adjacent to the oil line 13 to keep the oil in a liquified form in transit to the nozzles 14. Thermal insulation 15 may be provided around the steam and oil lines to minimize heat losses. In one nozzle embodiment, as shown in FIG. 2, the pressure of the gas and oil is controlled by a needle valve adjustment. A needle 17, threadedly secured within the valve housing 19, is effective for this purpose.

In accordance with the invention, the oil coating weight or mist density of the improved cold reducing system is controlled by the amount of oil pressure and gas pressure, e.g., air pressure, delivered to pneumatic atomizing nozzles plus the orifice opening or adjustment of the nozzle. Gas and oil pressures in the system need not exceed l0 p.s.i., so high pressure systems are not necessary. By varying pressure and orifice openings, nozzle outputs of from 0.15 gram/minute/nozzle to 31.5 grams/minute/ nozzle will be useful over a practical range of mill opera tions. Generally, the thickness of a lubricant coating on the work can be controlled by adjustment of the pressure. The oil and gas travel through the nozzle and mix at the nozzle tip where substantially complete atomization takes place. The atomization carries the oil mist to the strip where the oil is deposited at the desired weight. Because of the high efficiency of the lubricating system, it may be positioned very close to the roll bite, for example within 3 inches thereof. Of course, depending upon mill requirements, it may also be positioned at any desired location.

By employing an essentially all oil lubricant the problems inherent in water emulsions are avoided. Thus, product produced in accordance with the improved cold reducing process of the invention do not possess the streaked appearance frequently obtained with oil emulsion lubricating systems.

It is apparent that various changes and modifications may be made without departing from the invention. Thus, although the process disclosed herein is particularly useful with steel work, it is obviously capable of other applications. Accordingly, the scope of the invention should be limited only by the appended claims wherein what is claimed is:

1. An improved method of cold reducing metal work such as strip, sheet or the like with an atomized spray of lubricant, which comprises ejecting a liquified oil through a plurality of nozzles adapted to be positioned above and below the metal work entering the cold reduction mill, simultaneously ejecting a gas through said nozzles so that the gas will atomize the oil and blow it against the metal work, said gas being at a temperature 3 suflicient to preclude solidification of said oil, coating said work with a film of said atomized oil and thereafter cold reducing the coated work.

2. A process in accordance with claim 1 wherein said liquified oil is atomized by projecting said oil and gas through at least one nozzle at a nozzle flow rate of from 0.15 gram/minute/nozzle to 31.5 grams/minute/nozzle.

3. A process in accordance with claim 1 wherein said lubricant is normally viscous or solid at room temperature and is heated so that it is liquified prior to atomization.

4. A process in accordance with claim 3 wherein said lubricant consists essentially of neat oil.

4 References Cited UNITED STATES PATENTS 12/1938 Hurtt et a1 7243 4/1955 Turpin 7243 1/1957 Turpin 7243 1/1967 Fritzlen et a1. 7242 CHARLES W. LANHAM, Primary Examiner 10 E. M. COMBS, Assistant Examiner US. Cl. X.R. 

